Reversible rotary pump with vane flexing and shiftable cam

ABSTRACT

THE DISCLOSED REVERSIBLE ROTARY PUMP EMPLOYS AN IMPELLER HAVING VANES ADAPTED TO FLEX AND UNFLEX DURING ROTATION OVER AN ARCUATE CAM WHICH IS BODILY DISPLACED BY THE FLEXING VANES BETWEEN POSITIONS CORRESPONDING TO FLOW OF PUMP FLUID THROUGHT THE PUMP.

Feb. 23, 1971 HMS 3,565,557

REVERSIBLE ROTARY PUMP WITH VANE FLEXING AND SHIFTABLE CAM Filed Feb. 5, 1959 1 16. :0 r 14x l'a 0 IN yam roe LEA/N I H005 United States Patent US. Cl. 41832 9 Claims ABSTRACT OF THE DISCLOSURE The disclosed reversible rotary pump employs an impeller having vanes adapted to flex and unflex during rotation over an arcuate cam which is bodily displaced by the flexing vanes between positions corresponding to flow of pumped fluid through the pump.

BACKGROUND OF THE INVENTION This invention relates generally to rotary pumps, and more particularly concerns a vane-type rotary pump adapted for impeller reversal.

In the past, vane type rotary pumps of which I am aware have been disadvantaged by -virtue of an excess of parts including multiple vanes slidably mounted in an impeller, this construction increasing the possibility of malfunction. Good design dictates the necessity for simplicity; however, it has been thought necessary to employ such sliding vane arrangements where the impeller is to be subjected to periodic reversal, as in US. Pat. 3,397,598 to Zierich.

BRIEF SUMMARY OF THE INVENTION It is a major object of the invention to provide a reversible rotary pump of very simple construction, which overcomes the disadvantages of prior pumps and which in addition ofi'ers numerous advantages in construction and mode of operation. Basically the invention is embodied in a pump assembly that includes:

(a) A pump body forming a cavity and spaced ports through which fluid may pass through the cavity;

(b) An impeller located to rotate in the cavity and having vanes adapted to flex and unflex during such rotation; and

(c) An arcuate cam positioned in the path of impeller vane travel in the cavity and to be bodily displaced therein in response to vane engagement therewith and between a first position in which the impeller rotates counterclockwise to displace fluid through the cavity and said ports in one direction as the vanes flex and unflex in passing into and out of engagement with the cam, and a second position in which the impeller rotates clockwise to displace fluid through the cavity and ports as the vanes flex and unflex in passing into and out of engagement with the cam.

As will appear, the cam has opposite terminals, and a stop shoulder in the body is located to engage alternate terminals as the cam shifts its position in the body, one terminal extending proximate one of the ports in one cam position, and the other terminal extending proximate that one port in the other position of the cam. Also, the cam may advantageously comprise a section of a cylindrical sleeve and define an axis coincident with that of the impeller, the cavity being cylindrical to interfit the sliding cam. Further, the cam may typically subtend an angle of about 180 degrees between the terminals, the terminals being tapered and recessed as will be described to coact with the impeller vanes and ports in best flow pumping relation.

Patented Feb. 23, 1971 These and other objects and advantages of the invention, as well as the details of an illustrative embodiment will be more fully described in the following specification and drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical section taken through the pump body normal to the impeller axis;

FIG. 2 is a vertical section taken through the pump body parallel to the impeller axis;

FIG. 3 is an end elevation taken on line 3-3 of FIG. 2;

FIG. 4 is a bottom view taken on line 4-4 of FIG. 2;

FIG. 5 is a side elevation showing the sliding cam; and

FIG. 6 is an elevation taken on line 6-6 of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawings, the rotary pump assembly 10 includes a body or casing 11 and closure 12 forming a cylindrical cavity 13. Ports 14 and 15 are formed in the body at opposite sides of cavity axis 16, and may be tapped at 17 and 18 as indicated. Holes 22 indicate the locations of fasteners 22a to retain the cover to the body.

Centered within the cavity is the impeller 19 with its axis of rotation coinciding with the cavity axis 16. The impeller includes a hub 20 mounting a series of circularly spaced vanes 21 which are adapted to flex and unflex during impeller rotation. For this purpose, the vanes may consist of rubber or other suitable material; also, they extend, unflexed, generally from the hub to the inner cylindrical wall or bore 23 of the body, and widthwise between the cover 12 and the inner end wall 24 of the cavity, the cover 12 retaining the impeller in the cavity. The impeller vanes are shown as having lobes 25 engageable with wall 23, and reduced cross section webs 26 extending between the hub and the lobes. The impeller drive shaft extends at 27 through a sleeve bearing 28 in the body bore 29, and to the exterior.

In accordance with the invention, an arcuate cam 30 is located in the cavity 13 in the path of impeller vane travel and to be bodily displaced in the cavity in response to vane engagement therewith, and between a first position (shown in solid lines) in which the impeller rotates counterclockwise to displace fluid through the cavity and the ports (with port 14 acting as the inlet and port 15 the outlet) as the vanes flex and unflex in passing into and out of engagement with the cam; and a second position (shown by broken lines 3011) in which the impeller rotates clockwise to displace fluid through the cavity and the ports as the vanes flex and unflex in passing into and out of engagement with the cam. In this regard, the cam may advantageously comprise a portion of a cylindrical sleeve defining an axis coincident with axis 16, the cam then fitting the cavity, i.e. periph erally extending adjacent the body bore 23.

The radial thickness of the cam is such that it presents substantial interference to travel of the impeller vanes during impeller rotation, to the end that the vanes tend to drag the cam around axis 16. In this regard, the cam has opposite terminals 32 and 33 which are alternately engageable with a stop shoulder 34 projecting in the pump body, terminal 32 engaging the shoulder 34 when the impeller rotates counterclockwise, and terminal 33 engaging shoulder 34 when the impeller rotates clockwise. The stop shoulder may advantageously be defined by the tip of a set screw 35 projecting into the cavity at a location spaced from port 14 in a direction generally parallel to the axis 16.

Reference to FIGS. and 6 shows the cam terminals 32 and 33 as tapering toward the cylindrical locus defined by the cam periphery. This construction enables the impeller lobes to ride onto and off the cam inner periphery 36, with some gradualness, FIG. 1 showing the considerable extent to which the vanes become flexed when the lobes engage that inner periphery. In addition, the cam terminals are semi-circularly recessed at 37 and 38, for alternate registration with the two ports in each cam position, whereby flow through the cavity is not blocked by the cam. Note that the cam may typically have angularity between terminals 32 and 33 of about 180 degrees, promoting flexing and unflexing of the vanes with proper timing in relation to the ports for maximum pumping effect, as discussed below.

As seen in FIG. 1, the impeller vane riding up onto cam terminal 33 flexes toward the following vane, whereby the gap 40 between those vanes is reduced and fluid in that gap is expelled through port 15. Similarly, the gap 41 between vanes bracketing port 14 is expanded as the flexed vane travels 01f cam terminal 32 and progressively unflexes as it crosses that port, whereby suction is created to draw fluid into gap 41. Upon reversal of impeller rotation, the vanes immediately shift the cam 180 to the broken line position 30a, and the same direction pumping action then proceeds.

Finally, openings 50 are provided in the body for reception of bolts, or other fasteners to mount the pump. Also, an O-ring 51 seals 01f between shaft 27 and bearing 28.

I claim:

1. In a reversible rotary pump assembly,

(a) a pump body forming a cavity and spaced ports through which fluid may pass through the cavity,

(b) an impeller located to rotate in the cavity and having vanes adapted to flex and unflex during said rotation, and

(c) an arcuate cam positioned in the path of impeller vane travel in the cavity and to be bodily displaced therein in response to vane engagement therewith and between a first position in which the impeller rotates counter-clockwise to displace fluid through the cavity and said ports in one direction as the vanes flex and unflex in passing into and out of engagement with the cam, and a second position in which the impeller rotates clockwise to displace fluid through the cavity and said ports as the vanes flex and unflex in passing into and out of engagement With the cam.

2. The pump assembly of claim 1 wherein the cam has opposite terminals, and including a stop shoulder in the pump body and located to engage one of said terminals in said first position and another of said terminals in said second position.

3. The pump assembly of claim 2 wherein one cam terminal extends proximate one of said ports in one of said cam positions, and the other cam terminal extends proximate said one port in the other of said cam positions.

4. The pump assembly of claim 2 wherein the cam comprises a portion of a cylindrical sleeve and defining an axis which is the same as the axis of impeller rotation, the cavity being cylindrical and the cam fitting the cavity.

5. The pump assembly of claim 4 wherein the angle between said terminals as measured about said axis is about 6. The pump assembly of claim 1 wherein said cavity is sunk in one side of said body, and including a closure connected to said body in covering relation to said cavity and retaining said cam for rotation in said cavity.

7. The pump assembly of claim 3 wherein said stop shoulder is defined by a screw tip projecting into said cavity at a location spaced from said one port in a direction generally parallel to the axis of impeller rotation.

8. The pump assembly of claim 3 wherein the cam terminals form recesses alternately registrable with said one port in said cam positions.

9. The pump assembly of claim 4 wherein said terminals taper toward the cylinder defined by the cam periphery.

References Cited UNITED STATES PATENTS 1,850,567 3/1932 Roessler 230-137 2,414,187 1/1947 Borsting 1031 17U 2,855,853 10/1958 Yaugher et al 103117 2,856,859 10/1958 Baade et a1 103-117 2,971,469 2/1961 McLean 1031 17 FOREIGN PATENTS 1,291,630 3/1962 France 103117 769,378 3/1957 Great Britain 103-117 F CARLTON R. CROYLE, Primary Examiner W. J. GOODLIN, Assistant Examiner US. Cl. X.R. 

